Codebook subset restriction for frequency-parameterized linear combination codebooks

Abstract

A wireless device, a network node and methods are disclosed. According to one aspect, a method includes receiving an indication of a maximum power level associated with a spatial-domain basis vector. The method includes determining whether a combination of values of the plurality of amplitude coefficients results in exceeding the maximum power level. The method further includes, responsive to determining that a combination of values of the plurality of amplitude coefficients results in exceeding the maximum power level, not reporting the combination of values in a channel state information, CSI, report.

What is claimed is: 
     
       1. A method in a network node for codebook subset restriction, CBSR, of a Type II codebook, the method comprising:
 jointly restricting a maximum power level of amplitude coefficients of a spatial-domain basis vector of the codebook by restricting a square root of a sum of squares of the amplitude coefficients to be less than a maximum power threshold associated with a beam corresponding to the spatial-domain basis vector; and 
 indicating the maximum power threshold to a wireless device, WD, to be used by the WD for determining whether the square root of the sum of the squares of the amplitude coefficients exceeds the maximum power threshold. 
 
     
     
       2. A network node for codebook subset restriction, CBSR, of a Type II codebook, the network node comprising:
 processing circuitry configured to jointly restrict a maximum power level of a amplitude coefficients of a spatial-domain basis vector of the codebook by restricting a square root of a sum of squares of the amplitude coefficients to be less than a maximum power threshold associated with a beam corresponding to the spatial-domain basis vector; and 
 a radio interface in communication with the processing circuitry, the radio interface configured to indicate the maximum power threshold to a wireless device, WD, to be used by the WD for determining whether the square root of the sum of the squares of the amplitude coefficients exceeds the maximum power threshold. 
 
     
     
       3. The network node of  claim 2 , wherein the jointly restricting is applied to multiple layers of transmission. 
     
     
       4. The network node of  claim 2 , wherein the jointly restricting is applied separately for each of a plurality of layers of transmission. 
     
     
       5. The network node of  claim 2 , wherein the jointly restricting is applied separately for each of a plurality of polarizations. 
     
     
       6. The network node of  claim 2 , wherein the jointly restricting is applied separately for each of a plurality of sets of antenna ports. 
     
     
       7. The network node of  claim 2 , wherein the jointly restricting is applied for each of a plurality of beams in subset of beams. 
     
     
       8. The network node of  claim 7 , wherein the indicating includes indicating a maximum power level and indicating for which beams in the subset of beams the maximum power level applies. 
     
     
       9. The network node of  claim 2 , wherein a maximum power threshold associated with a beam is selected from a range that includes zero, zero indicating that the beam is not to be used by the WD. 
     
     
       10. A method in a wireless device, WD, for codebook subset restriction, CBSR, of a Type II codebook, the method comprising:
 receiving an indication of a maximum power threshold associated with a spatial-domain basis vector of the codebook; 
 determining whether a square root of the sum of squares of amplitude coefficients of the spatial domain vector exceeds the maximum power threshold; and 
 responsive to determining that the square root of the sum of squares of the amplitude coefficients exceeds the maximum power threshold not reporting the amplitude coefficients in a channel state information, CSI, report. 
 
     
     
       11. A wireless device, WD, for codebook subset restriction, CBSR, of a Type II codebook, the WD comprising:
 a radio interface configured to receive an indication of a maximum power threshold associated with a spatial-domain basis vector of the codebook; and 
 processing circuitry in communication with the radio interface, the processing circuitry configured to:
 determine whether a square root of the sum of squares of amplitude coefficients of the spatial domain vector exceeds the maximum power threshold; and 
 responsive to the determining that the square root of the sum of squares of the amplitude coefficients exceeds the maximum power level threshold not reporting the amplitude coefficients in a channel state information, CSI, report. 
 
 
     
     
       12. The WD of  claim 11 , wherein the determining is applied to multiple layers of transmission. 
     
     
       13. The WD of  claim 11 , wherein the determining applied separately for each of a plurality of layers of transmission. 
     
     
       14. The WD of  claim 11 , wherein the determining is applied separately for each of a plurality of polarizations. 
     
     
       15. The WD of  claim 11 , wherein the determining is applied separately for each of a plurality of sets of antenna ports. 
     
     
       16. The WD of  claim 11 , wherein the determining is applied for each of a plurality of beams in a subset of beams. 
     
     
       17. The WD of  claim 16 , wherein the determining includes determining which beams in the subset of beams the maximum power level applies. 
     
     
       18. The WD of  claim 11 , wherein the determining includes comparing the combination of values to a maximum power threshold selected from a range that includes zero, zero indicating that the beam is not to be used by the WD. 
     
     
       19. The WD of  claim 11  wherein the maximum power level is relative to a total precoder power. 
     
     
       20. The WD of  claim 11 , wherein the maximum power level is associated with a particular one of a plurality of polarizations. 
     
     
       21. The WD of  claim 11 , wherein the maximum power level is associated with a particular transmission layer. 
     
     
       22. The WD of  claim 11 , wherein the maximum power level is associated with a group of transmission layers.